Process for improving color of polycondensates

Abstract

The present invention relates to a process of preparing a polycondensate in the presence of a fluorescent whitening agent and at least one phosphonate, and/or phosphinate. Further aspects of the invention are a polyester prepared according to this process and composition comprising a polycondensate, a fluorescent whitening agent and at least one phosphonate and/or phosphinate. Yet another aspect is the use of a fluorescent whitening agent and at least one phosphonate and/or phosphinate for improving the color of a polycondensate.

1 . A process for the preparation of a polycondensate in a condensation reaction of monomers or oligomers or the modification of a polycondensate by melt processing or solid-state polycondensation of the polycondensate, comprising adding during the polycondensation reaction 
 a1) a compound of formula (I)                          wherein    R 103  is H, C 1 -C 20 alkyl, unsubstituted or C 1 -C 4 alkyl-substituted phenyl or naphthyl,    R 104  is hydrogen, C 1 -C 20 alkyl, unsubstituted or C 1 -C 4 alkyl-substituted phenyl or naphthyl; or    M r+ /r,    M r+  is an r-valent metal cation or the ammonium ion,    n is 0, 1, 2, 3, 4, 5 or 6, and    r is 1, 2, 3 or 4;    Q is hydrogen, —X—C(O)—OR 107 , or a radical                          R 101  is isopropyl, tert-butyl, cyclohexyl, or cyclohexyl which is substituted by 1-3 C 1 -C 4 alkyl groups,    R 102  is hydrogen, C 1 -C 4 alkyl, cyclohexyl, or cyclohexyl which is substituted by 1-3 C 1 -C 4 alkyl groups,    R 105  is H, C 1 -C 18 alkyl, OH, halogen or C 3 -C 7 cycloalkyl;    R 106  is H, methyl, trimethylsilyl, benzyl, phenyl, sulfonyl or C 1 -C 18 alkyl;    R 107  is H, C 1 -C 10 alkyl or C 3 -C 7 cycloalkyl; and    X is phenylene, C 1 -C 4 alkyl group-substituted phenylene or cyclohexylene; or    a2) a compound of formula (II)                        wherein    R 201  is hydrogen, C 1 -C 20 alkyl, phenyl or C 1 -C 4 alkyl substituted phenyl; biphenyl, naphthyl, —CH 2 —O—C 1 -C 20 alkyl or —CH 2 —S—C 1 -C 20 alkyl,    R 202  is C 1 -C 20 alkyl, phenyl or C 1 -C 4 alkyl substituted phenyl; biphenyl, naphthyl, —CH 2 —O—C 1 -C 20 alkyl or —CH 2 —S—C 1 -C 20 alkyl, or R 1  and R 2  together are a radical of the formula III                          wherein    R 203 , R 204  and R 205  independently of each other are C 1 -C 20 alkyl, phenyl or C 1 -C 4 alkyl substituted phenyl;    R 206  is hydrogen, C 1 -C 18 alkyl or the ion of an alkali metal or the ammonium ion or    R 206  is a direct bond, which forms together with R 202  an aliphatic or aromatic cyclic ester; or      a3) a compound of formula (I) and formula (II); and    b) a fluorescent whitening agent selected from the group consisting of compounds of formulae 1-8 and mixtures thereof                          in which formulae                          R 3  is an unsubstituted or substituted alkyl or aryl group;    R 4  is M, or an unsubstituted or substituted alkyl or aryl group;    R 5  is hydrogen; an unsubstituted or substituted alkyl or aryl group; or —NR 7 R 8 , wherein R 7  and R 8  are each independently of the other hydrogen or an unsubstituted or substituted alkyl or aryl group, or R 7  and R 8  together with the nitrogen atom linking them form a heterocyclic radical;    R 6  is hydrogen, or an unsubstituted or substituted alkyl or aryl group;    R 2  is hydrogen; an unsubstituted or substituted alkyl or aryl group; or a radical of formula                          —N(CH 2 CH 2 OH) 2 , —N[CH 2 CH(OH)CH 3 ] 2 , —NH—R 4 , —N(R 4 ) 2  or —OR 4 ; or    R 1  and R 2  are each independently of the other —OH, —Cl, —NH 2 , —O—C 1 -C 4 alkyl, —O-aryl, —NH—C 1 -C 4 alkyl, —N(C 1 -C 4 alkyl) 2 , —N(C 1 -C 4 alkyl)(C 1 -C 4 hydroxyalkyl), —N(C 1 -C 4 hydroxyalkyl) 2 , —NH-aryl, morpholino or —S—C 1 -C 4 alkyl(aryl);    R 9  and R 10  are each independently of the other hydrogen, C 1 -C 4 alkyl, phenyl or a radical of formula                          R 11  is hydrogen, —Cl or SO 3 M;    R 12  is —CN, —SO 3 M, —S(C 1 -C 4 alkyl) 2  or —S(aryl) 2 ;    R 13  is hydrogen, —SO 3 M, —O—C 1 -C 4 alkyl, —CN, —Cl, —COO—C 1 -C 4 alkyl or —CON(C 1 -C 4 alkyl) 2 ;    R 14  is hydrogen, —C 1 -C 4 alkyl, —Cl or —SO 3 M;    R 15  and R 16  are each independently of the other hydrogen, C 1 -C 4 alkyl, —SO 3 M, —Cl or —O—C 1 -C 4 alkyl;    R 17  is hydrogen or C 1 -C 4 alkyl;    R 18  is hydrogen, C 1 -C 4 alkyl, —CN, —Cl, —COO—C 1 -C 4 alkyl, —CON(C 1 -C 4 alkyl) 2 , aryl or —O-aryl;    M is hydrogen, sodium, potassium, calcium, magnesium, ammonium, mono-, di-, tri- or tetra-C 1 -C 4 alkylammonium, mono-, di- or tri-C 1 -C 4 hydroxyalkylammonium, or ammonium di- or tri-substituted by a mixture of C 1 -C 4 alkyl and C 1 -C 4 hydroxyalkyl groups; and    n 1 , n 2  and n 3  are each independently of the others 0 or 1.    
   
   
       2 . A process according to  claim 1 , wherein the polycondensate is polyethylene therephthalate (PET), polybutylene therephthalate (PBT), polyethylenenaphthenate (PEN), a copolyester, PA 6, PA 6, 6, or is a polycarbonate containing bisphenol A, bisphenol Z or bisphenol F linked via carbonate groups.  
   
   
       3 . A process according to  claim 1 , wherein the polycondensate is PBT, PET or a copolymer with PBT or PET.  
   
   
       4 . A process according to  claim 1 , wherein the polycondensate exhibits a L value, which is greater than 80 and a b value which is less than 2, as measured with a spectrometer according to ASTM D1925.  
   
   
       5 . A process according to  claim 1 , wherein a compound of formula (I) as component a1) is added.  
   
   
       6 . A process according to  claim 5  wherein the compound of formula (I) is of the formula P1 or P2  
     
       
         
         
             
             
         
       
     
   
   
       7 . A process according to  claim 1  wherein the compounds of formulae 1-8 are the compounds  
     
       
         
         
             
             
         
       
     
   
   
       8 . A process according to  claim 1  wherein the compounds of formula (I) or (II) are added in an amount from 0.01 to 5% by weight, based on the weight of the polycondensate.  
   
   
       9 . A process according to  claim 1  wherein the compounds of formulae 1-8 are added in an amount of 0.001 to 0.5% by weight, based on the weight of the polycondensate.  
   
   
       10 . A process according to  claim 1  wherein the weight ratio of the compounds according to formula (I) and (II) to the compounds of formulae 1-8 is from 50:1 to 1:1.  
   
   
       11 . A process according to  claim 1  wherein additionally a polyanhydride is added, which has 2-8 anhydride functions.  
   
   
       12 . A process according to  claim 1  wherein a further polyfunctional compound is added, selected from the group consisting of a polyfunctional hydroxyl compound (polyol), a polyfunctional epoxy compound, a polyfunctional amine compound (polyamine), a polyfunctional aziridine compound (polyaziridine), a polyfunctional isocyanate compound (polyisocyanate), a polyfunctional oxazoline compound (polyoxazoline), a polyfunctional thioalcohol, and combinations thereof.  
   
   
       13 . A polycondensate obtained in a process according to  claim 1 .  
   
   
       14 . A composition comprising a polycondensate and 
 a1) a compound of formula (I); or    a2) a compound of formula (II); or    a3) a compound of formula (I) and (II) and    b) a compound of formulae 1-8 according to  claim 1 .    
   
   
       15 . (canceled)